Question 1

Which of the following best describes the sequence of excitation in the intrinsic cardiac conduction system during a normal heartbeat?

Accepted Answer

Sinoatrial node → Atrioventricular node → Atrioventricular bundle → Bundle branches → Purkinje fibers

Question 2

A patient presents with an ECG showing absent P waves and a heart rate of 45 beats per minute. Which conduction abnormality is most likely present?

Accepted Answer

Junctional rhythm

Question 3

During the cardiac cycle, which event directly causes the first heart sound (S1)?

Accepted Answer

Closing of the atrioventricular valves

Question 4

Which formula correctly calculates stroke volume (SV)?

Accepted Answer

$$SV = EDV - ESV$$

Question 5

A patient with persistent high blood pressure is at risk for which change in cardiac function?

Accepted Answer

Increased afterload, increased end systolic volume, and reduced stroke volume

Question 6

Which ion is primarily responsible for the plateau phase of the action potential in contractile cardiac muscle cells?

Accepted Answer

Calcium ($$Ca^{2+})$$

Question 7

Which of the following would most likely cause a heart murmur characterized by a high-pitched sound or clicking?

Accepted Answer

Stenotic valve

Question 8

Which of the following is a positive inotropic agent that increases contractility of the heart?

Accepted Answer

Digitalis

Question 9

What is the effect of hypocalcemia on the heart?

Accepted Answer

Slows heart rate and weakens contraction

Question 10

Which phase of the cardiac cycle is characterized by all four heart valves being closed and no change in ventricular volume?

Accepted Answer

Isovolumetric contraction

Question 11

A patient with left-sided heart failure is most likely to develop which clinical symptom?

Accepted Answer

Pulmonary congestion and edema

Question 12

Which structure in the fetal heart allows blood to bypass the pulmonary circulation by connecting the right and left atria?

Accepted Answer

Foramen ovale

Question 13

Which ECG finding is most indicative of acute cardiac ischemia?

Accepted Answer

Elevated or depressed S-T segment

Question 14

Which of the following best explains the Frank-Starling law of the heart?

Accepted Answer

Increased preload (EDV) increases stroke volume due to greater stretch and contractile force

Question 15

Which formula correctly calculates cardiac output (CO)?

Accepted Answer

$$CO = SV 	imes HR$$

Question 16

Which of the following would most likely result in a decreased heart rate?

Accepted Answer

Release of acetylcholine by the vagus nerve

Question 17

A patient with a ventricular septal defect will most likely experience which of the following?

Accepted Answer

Mixing of blood between the two ventricles, with more blood shunted from left to right

Question 18

Which of the following is true regarding the action potential of cardiac pacemaker cells?

Accepted Answer

Depolarization is due to $$Ca^{2+}$$ influx

Question 19

Which condition is characterized by rapid, irregular contractions of the ventricles, resulting in clinical death without immediate intervention?

Accepted Answer

Ventricular fibrillation

Question 20

Which of the following would most likely increase both heart rate and contractility during exercise?

Accepted Answer

Sympathetic stimulation and release of epinephrine

Heart Physiology: Electrical and Mechanical Events, Regulation, and Development

Study Guide - Practice Questions